Sensitivity to Myroxylon pereirae resin (balsam of Peru). A study of 50 cases.

The Myroxylon pereirae resin (MP; balsam of Peru) is a natural resin used in the local treatment of burns and wounds. M. pereirae extracts and distillates are very often contained in a wide range of cosmetic products and causes frequently allergic contact dermatitis - to the extent of being considered an allergy marker to perfumes. We have carried out a retrospective study of 863 patients who have been submitted to patch tests from January 2002 to June 2004. A total of 50 patients were positive to MP. Thus, the prevalence was 5.79%, slightly higher in men (7.32%) than in women (4.91%). The positive patch tests were relevant in 64%. Over the last years, it appears that there is a clear increase of the prevalence of the sensitization to MP in all the studies published. We observe an increase of the prevalence especially in aged patients, where the sensitization is linked with the use of topical medications secondary to stasis dermatitis. The high frequency of allergy to MP in our area might be associated with manipulation of citrus fruits. The increasing use of cosmetic products by the male population can also be held responsible for the higher sensitization rate in this group of patients.